The invention relates generally to shielding devices and more particularly to lids for shielding cans used to shield electronic components from electromagnetic interference (EMI).
Many electronic apparatuses, such as computer products, cellular phones and the like, include electronic components, such as printed circuit boards (PCBs) and integrated circuits (ICs). It is often desirable to isolate the electronic component) to prevent the EMI from the component from affecting other electronic components incorporated in the apparatus or for shielding the component from EMI emitted by other sources.
Many electronic components generate significant amounts of heat. Excessive heat build up can lead to reduced product life and reliability. Thus, various constructions have been proposed for removing heat generated by electronic components.
Existing constructions and methods for simultaneously removing heat from an electronic component and for shielding the component have not always proven to be fully satisfactory, such as in view of the complexity, size, costs or effectiveness of these constructions and methods. Accordingly, it is desirable to provide an improved construction and method for shielding an electronic component and removing heat from the component, which overcomes inadequacies of the prior art.
Generally speaking, in accordance with the invention, an improved construction and method are provided for electronically shielding an electronic component and for removing heat generated by the component. The construction and method involves the use of a shielding can, formed with EMI shielding material that surrounds the electronic component and a lid or cap that both contacts and forms a heat sink with the component and also provides a shielding effect as it acts as the cap for the shielding can.
The can may be formed with side walls and an opening, such as a window located at the top thereof. The lid can be in the form of a resilient member formed of electrical and heat conductive material and preferably having heat dispersing fins, which snaps in place at the opening in the can, and maintains good contact with the electronic component. In preferred embodiments of the invention, the lid is spring biased against the component. The shielding lid can be formed as a snap in lid that includes a contacting surface to draw heat from the heat producing component and outwardly extending fins which transfer heat drawn from the component to the surrounding environment.
The shielding can may be any known electrical housing with any number of sidewalls and with a single or stepped horizontal top surface having one or more openings, each providing shoulder for the snap-in lid. The can may include a window at the top surface thereof and side walls that extend up and then can extend partially into the interior of the can, to provide a shoulder defining the opening. The lid can include a camming surface which snaps under the shoulder and biases the lid down onto the heat producing component, so as to maintain good thermal contact between the lid and the component. In certain embodiments of the invention, heat conductive material, such as electronically insulating heat conductive material, in the form of gels, coatings, paints, rubbers, elastomers, polymers and resins can be disposed at the interface of the lid and the electronic component.
Accordingly, it is an object of the invention to provide improved structures for shielding an electronic component and for drawing heat from the component;
Another object of the invention is to provide improved methods for shielding an electronic component and for drawing heat from the component.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the article possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure. The scope of the invention will be indicated in the claims.